Thread-lead indicator.



F. G. LINDGREN.

THREAD LEAD INDICATOR.

APPLICATION FILED MAY 9. ma

1,297,194. Patented Mar. 11, 1919.

f ha anx"dfmnnennn;or narron; onto, AfssIGNoaro THEsHErrIELn MACHINE &

.To dllwkoin it m ay concern grooi. eoomrannforfnaxron; 0310, a oon'roaarxon or OHIO.

f"'rnaEAn-LEAn INDICATOR.

1,297,194. v I s fis o tate en. atentea Mar. 11, 1919. E: #ApplicationfiledMayB, 191s. Seria1No.'233,570. H r

thread leads are ts be-i tested, is held be- Be it known. that-I, FRANK G.;LINDGREN, a citizen of the United States,,residing at Dayton,-in the county. ofMontgomery and State of Ohio, have invented certain new and useful Improvements in Thread-Lead Indicators,-of which the following is a specification. 1 v new and useful improvements in thread lead indicators.

-- .The principal object ofithe invention is to provide a thread leadindicatorin which an indicator ofa standard type andJohansson measuring-blocks are combined and cooperate to accurately indicate-the thread lead: of "a" screw.

The preferred formof embodiment of my invention isillustrated in the accompanying drawings, of which Figureliis a perspective .view of my improved} thread. leadindicatorin engagement. with a screw; thread. Fig.2 is a topplan view of said-indicating.

device and Fig. ,3. is, a side view thereof. 1 Throughout the 1 specification and draw- --ings, similar reference characters .denote .cor- =respond1ng parts.

In a detailed descriptionof the preferred form of embodiment :of my invention, the numeral 1 vdesignates'a base upon which rests, near its front side, a longitudinal -dovetailedsupport 2.for aicarriage 3. This carriage in turn has a dovetailed transverse grooveiin its top to receive a cross slide 4 which carries a curved dial 6 whose graduations thepointed end of an indicator arm 7 traverses, said indicator' arm being pivotally connected at its rear end'to pin 7 in the upturned end 7 of a horizontal 11181111 her 8 supported on said cross slide.mPro-,;

jecting from the pivoted end of the indicator arm 7 into a slot provided in'a lever arm 9 below it, is a pin 10, whereby, when the lever arm 9 is moved, as will hereinafter be described, the indicator arm 7 will be turned thereby to bring its pointed end to an indication on the dial 6 which is secured on the front end of the horizontal member 8-as shown in Fig. 3.

The lever arm 9 is pivotallysecured by a pin 10 in a front projection ll on the horizontal member 8, the outer end of said lever arm containing a bore adapted to receive one end of a point 12-adapted to en gage one side'of a thread of arscrew 13. The latter, or any other screw or gagewhose A of various sizes. -.on the dlal fi to ascertain the graduation go tween'the center'14 ofaa headstock l6 and the center l5 of atailstock 17, slidable on an elongated supporting member 185 which rests upon the base ,1 adjacent the supporting member,2.

; Secured tov the'front endofthe supportingmember 2 isjan end piece 19 of the same width as the latter and terminating in. a

operate with the dial 6 and indicator arm f7 for, the purpose of indicating the accuracy 7 5 of the thread lead of the screw being tested.

By means-ofja screw 23 which extends @through-a'threaded collar 24 carried by the slide;.-4,-j-f;or engagement with the carriage 3, the point beyond which the slide can not .benioved inthe'direction'of, the screw 13 mayberadjustably controlled. V

= In operation, the indicator point 12 is placedagainst one side ofa; thread of a screw, asQShOwn inFig; 2. A-small indicator 35 point isused fora fine thread, and a large one for a 'large, thread, the front endof the lever arm 9 being adapted to receive points A readingjis then taken upon,or near-which, thepointed end of the arm 7 stands. One or more blocks 22 are thenz placedupon, or; removed'from, the

top-of the supporting member 2 between After being drawn the studs 20 and 21. outwardly, the cross slide 4: is moved by the carriage 3 to bring the point 12 into engagement with the corresponding side of the next thread selected, depending upon the thickness of the block added or .withdrawn. The cross slide at is then pushed inwardly to bring the indicator point into engagement with the corresponding side of the selected thread, while the blocks 22 are being firmly gripped by the studs 20 and 21,' and a reading on the dial then taken. If it is found to be the same as the first reading, the thread is correct.

For example, if the lead or distance from one thread to the other is one eighth of an inch, and a reading has been taken on one thread, an eighth inch block is. then added or removed and the indicator point 12 placed against the corresponding side of the next thread, or against the corresponding side of the second thread if a fourth inch block has been added or removed. If the reading then taken on the dial is the same as the first, the thread is correct; if not, it is drunken or inaccurate.

It is thus seen that by adding or removing the blocks 22 and taking a reading on the dial 6- each time the indicator point is placed in engagement with a corresponding si le' of a succeeding thread, the correctness of the thread lead is accurately indicated.

Having described my invention, I claim:

1. In a thread lead indicator, the combination with a slide support of a carriage slidingly movable on the latter, an indicat ing device slidingly mova ble on the carriage, a lever arm located on said carriage for operating said indicating device, having an end portion adapted to rest against the corr spending sides of the threads of the screw to be tested, a stop on said support, and measuring blocks adapted to be placed upon the latter between said stop and said carriage, to cooperate with the latter in testing the accuracy of the thread leads of said screw.

In a thread lead indicator, the combination with a. slide support, of a carriage laterally movable on said support, an indicating device transversely movable on said carriage toward and away from a screw to he tested, a lever arm located on said carriage for operating said indicating device, having an end portion adapted to rest against the corresponding sides of the threads of the screw, a. stop on said support, and measuring blocks adapted to be placed upon the latter between said stop and the movable carriage, to coeperate with the indicating device in testing the accuracy of the thread leads of said screw.

Games at this patent may be obtained for five 3. In a thread lead indicator, the combination with a slide support, of a carriage laterally movable on said support, an indicating device transversely movable on said carriage toward and away from a screw to be tested, a lever arm located on said car riage for operating said indicating device, having an end portion adapted to rest against the corresponding sides of the threads of the screw, a stop on said support, a stud projecting inwardly from said stop, a second stud projecting from said carriage, toward and in alinement with the first stud, and Johansson measuring blocks adapted to be placed upon said slide: support between said studs, to cooperate with the indicating device in testing the accuracy of the thread leads of the screw.

4. In a thread lead indicator, the combination with a slide support, of a carriage laterally movable on said support, an indieating device transversely movable on said carriage, a second slide support adjacent the first, a headstock and a tailstock ,.on the latter, a. screw to be tested held thereby, and toward and away from which said indicating device is movable, a lever arm located on said carriage for operating said indicating device, having an end portion adapted to rest against the corresponding sides of the threads of said screw, a stop on the first slide support, a stud projecting inwardly from said stop, a second stud projecting from said carriage, toward and in aline- 'ment with the first stud, and Johansson measuring blocks adapted to be placed upon the first slidesupport between said studs 'to cofiiperate with the indicating device in testing the accuracy of the thread leads of said screw. H

In testimony whereof Ihave' hereunto set my hand this 7th day of May, 1918'.

FRANK G. LINDGREN.

Witness 2 HOWARD S. SMITH cents each, by addressing the ficramissioner of Patents,

Washington, D. G. 

